Polyester compositions of low residual aldehyde content

ABSTRACT

A mixture of a polyester, such as poly(ethylene terephthalate) PET, and an additive combination, when extrusion compounded exhibits a lower residual acetaldehyde content than does PET alone when similarly treated. The additive combination comprises compounds selected from at least two groups wherein the groups are (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer, (ii.) polyhydric alcohols and (iii.) polyacrylamide, polymethacrylamide or copolymer of acrylamide or methacrylamide. The invention pertains to any polyester used in the manufacture of bottles or containers which in turn are used to store consumer materials, especially food, beverages and most especially water.

[0001] This application claims the benefit under 35 USC 119(e) of U.S.Provisional Application Serial Nos. 60/259,140, filed Dec. 29, 2000 and60/287,925, filed Apr. 30, 2001.

[0002] A mixture of a polyester, such as poly(ethylene terephthalate)PET, and an additive combination, when extrusion compounded exhibits alower residual acetaldehyde content than does PET alone when similarlytreated. The additive combination comprises compounds selected from atleast two groups wherein the groups are (i.) poly(vinyl alcohol) orethylene/vinyl alcohol copolymer, (ii.) polyhydric alcohols and (iii.)polyacrylamide, polymethacrylamide or copolymer of acrylamide ormethacrylamide. The invention pertains to any polyester used in themanufacture of bottles or containers which in turn are used to storeconsumer materials, especially food, beverages and most especiallywater.

BACKGROUND OF THE INVENTION

[0003] U.S. Pat. No. 4,361,681 teaches that polyester containinganhydride end-cap agents have a reduced acetaldehyde generation rate.

[0004] U.S. Pat. No. 5,459,224 discloses polyesters having4-oxybenzylidene end-cap agents to impart improved weatherability andphotostability, but no mention is made as to evolution of acetaldehyde.However, it is indicated that such polyesters are suitable for food andbeverage packaging.

[0005] Polyesters can be synthesized by a number of routes known in theart using a variety of catalyst systems. EP 826,713 A1 teaches thatlower levels of acetaldehyde occur during copolymerization of PET when aphosphite such as bis(2,4-di-tert-butylphenyl)pentaerythritol phosphiteis present during the polymerization.

[0006] U.S. Pat. Nos. 4,837,115; 5,258,233; 5,266,413; 5,340,884;5,648,032 and 5,650,469; and WO 93/20147 A1; WO 93/23474 A1; WO 98/07786and WO 98/39388 teach the use of polyamides as a means of reducing theconcentration of acetaldehyde, presumably via a Schiff-base reactionwith the aldehyde, which is reversible in the presence of water.

[0007] U.S. Pat. No. 5,856,385 teaches the use of polyamide or amide-waxto reduce the level of acetaldehyde which occurs when sorbitol-basedclarifying agent is heated in polyolefins.

[0008] U.S. Pat. No. 5,011,890 describes the suppression of acetaldehydeformation when polyacrylamide, polymethacrylamide or selected acrylamideor methacrylamide copolymers are used in polyacetals. A requirement isthat the polyacrylamide or polymethacrylamide must be “non-meltable” atthe processing temperature of polyacetal. There is no suggestion in thispatent that using polyacrylamide or polymethacrylamide in a polyesterwould reduce the concentration of acetaldehyde in a melt-mixed blendsuch as via extrusion.

[0009] Copending application Ser. Nos. 09/603,505 and 09/603,506disclose the use of poly(vinyl alcohol) or an ethylene/vinyl alcoholcopolymer and polyhydric alcohols, respectively, towards reducing theresidual aldehyde content in PET. Copending application Ser. No.09/666,679 discloses the use of polyacrylamide, polymethacrylamide or anacrylamide or methacrylamide copolymer with at least one ethylenicallyunsubstituted comonomer towards reducing the residual aldehyde contentin PET.

[0010] U.S. Pat. No. 4,394,470 discloses a polyethylene terephthalatemolding composition with a caramel colorant. The caramel colorant mayhave been formed in situ from a mono- or disaccharide.

[0011] U.S. Pat. No. 5,681,879 discloses a flame-retardant polyestercomposition comprising a polyester resin, a polyhydric alcohol havingnot less than 3 hydroxyl groups, an inorganic flame retardant and ahalogen-based flame retardant.

[0012] WO 00/66659 discloses molding compositions comprising PET andpolyhydric alcohol additives for the reduction of acetaldehydeformation.

[0013] WO 01/00724 discloses the use of polyols towards reducingacetaldehyde formation in extruded products of PET.

[0014] The invention is useful for any polyester where aldehydiccompounds, especially acetaldehyde, are formed or evolved during thermalprocessing of said polyester. Thermal processing of PET includes thesynthesis of PET, thermal exposure during solid state polymerization(SSP), any injection molding, injection-blow molding or stretch-blowmolding used in the manufacture of preforms, parissons or bottles andcontainers, or extrusion of film, or during any melt processing of PETabove its glass transition temperature and below its decompositiontemperature.

[0015] The instant invention provides for a lower amount of contaminants(e.g. aldehydes) in PET water bottles thus providing for improved tasteor flavor in bottled water or other bottled beverages in said PETcontainers. The reduction in the amount of acetaldehyde is highlybeneficial in this respect. Acetaldehyde is known as a decompositionproduct of polyesters such as PET. The acetaldehyde imparts anundesirable taste or flavor to bottled water stored in PET bottles. Ithas been a long sought objective of the industry to reduce the level ofacetaldehyde which migrates out of the PET bottle walls into the wateror other beverage stored therein. A number of engineering or designchanges to extruders, injection molding machines for preforms and bottlemaking machinery have been made to minimize formation of acetaldehydewhen poly(ethylene terephthalate) PET is processed. Modification to thePET composition itself have been made to lower its melting point or itsmelt viscosity in order to allow less severe thermal or mechanicaldamage when PET is processed into preforms or bottles.

[0016] The particular additive combination of the present inventionprovide unexpected benefits in polyester compositions. Certain additivecombinations are synergistic towards prevention of aldehyde formationduring melt processing. Certain other additive combinations unexpectedlyprovide an optimal balance of low color, low haze and high aldehydeinhibition. “Haze” is an undesirable, perceptible graying effect.

DETAILED DISCLOSURE

[0017] The instant invention pertains to a polyester composition,stabilized against the formation of aldehydic contaminants during meltprocessing of said composition, which comprises

[0018] (a) a polyester, and

[0019] (b) an effective stabilizing amount of an additive combination,wherein the additives are selected from at least two different groups,wherein the groups are

[0020] (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer,

[0021] (ii.) polyhydric alcohols and

[0022] (iii.) polyacrylamide, polymethacrylamide or an acrylamide ormethacrylamide copolymer with at least one ethylenically unsubstitutedcomonomer.

[0023] The polyester of component (a) is 95-99.9% by weight of thestabilized composition; and the additive combination of component (b) is5 to 0.1% by weight of the stabilized composition. Each additiveselected from the groups (i.), (ii.) and (iii.) may be from 1 to 99% byweight of the total additive combination of component (b).

[0024] The present additive combinations of component (b) may be binarycombinations, for example, a compound from group (i.) and a compoundfrom group (ii.), or a compound from group (ii.) and a compound from(iii.). The additive combinations may, for example, also be ternarycombinations, e.g., a compound from each of the groups (i.), (ii.) and(iii.).

[0025] The polyester of component (a) has dicarboxylic acid repeat unitsselected from the group consisting of aromatic dicarboxylic acids having8 to 14 carbon atoms, aliphatic dicarboxylic acids having 4 to 12 carbonatoms, cycloaliphatic dicarboxylic acids having 8 to 12 carbon atoms,and mixtures thereof.

[0026] Preferably such diacids are terephthalic acid, isophthalic acid,o-phthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylicacid, cyclohexanediacetic acid, diphenyl-4,4′-dicarboxylic acid,succinic acid, maleic acid, glutaric acid, adipic acid, sebacic acid andmixtures thereof.

[0027] Especially preferred are terephthalic acid, isophthalic acid and2,6-naphthalene dicarboxylic acid.

[0028] The diol or glycol portion of the polyester of component (a) arederived from the generic formula HO—R—OH where R is an aliphatic,cycloaliphatic or aromatic moiety of 2 to 18 carbon atoms.

[0029] Preferably such diols or glycols are ethylene glycol, diethyleneglycol, triethylene glycol, propane-1,3-diol, propane-1,2-diol,butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol,1,4-cyclohexanedimethanol, 3-methylpentane-2,4-diol,2-methylpentane1,4-diol, 2,2-diethyl-propane-1,3-diol,1,4-di-(hydroxyethoxy)benzene, 2,2-bis(4-hydroxycyclohexyl)-propane,2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane,2,2-bis-(3-hydroxyethoxyphenyl)propane,2,2-bis-(4-hydroxypropoxyphenyl)ethane and mixtures thereof.

[0030] Most preferably, the diol is ethylene glycol and1,4-cyclohexanedimethanol.

[0031] The polyester of component (a) is preferably poly(ethyleneterephthalate) PET or poly(ethylene 2,6-naphthalene-2,6-dicarboxylate);most preferably poly(ethylene terephthalate).

[0032] It is also contemplated that the polyester of component (a) canalso be a blend of polyesters or copolyesters including componentsmentioned above.

[0033] It is contemplated that the polyester of component (a) can bevirgin polymer or alternatively polymer recyclate. Additionally, it ispossible to combine 80-99% by weight of a polyester with 20-1% by weightof a concentrate where the concentrate comprises 10-90% by weight of apolyester carrier resin and 90-10% by weight of the additive combinationdescribed for component (b).

[0034] The novel polyester compositions provided by this invention areuseful in the manufacture of containers or packages for comestibles suchas beverages and food. Articles molded from these polyesters exhibitgood thin-wall rigidity, excellent clarity and good barrier propertieswith respect to moisture and atmospheric gases, particularly carbondioxide and oxygen.

[0035] The plastic containers and films of the present invention arerigid or flexible mono- and/or multi-layered constructions. Typicalmulti-layer constructions have two or more layer laminates, manufacturedeither by thermoforming, or extrusion of multi-layer flexible films, orextrusion of bottle “preforms” or “parissons” followed by subsequentblow molding of the preforms into bottles. In a multi-layer system,layers of any suitable plastic may be employed.

[0036] Multi-layered containers and films of this invention may forexample, be formed from layers of polyesters, polyolefins, polyolefincopolymers such as ethylene-vinyl acetate, polystyrene, poly(vinylchloride), poly(vinylidene chloride), polyamides, cellulosics,polycarbonates, ethylene-vinyl alcohol, poly(vinyl alcohol),styrene-acrylonitrile and ionomers, with the proviso that at least onelayer comprises a polyester composition of the present invention.

[0037] For both films and rigid packaging (bottles), typically theexterior layer, and innermost layer contacting the contents, arecomposed of polyesters such as PET or PEN [poly(ethylene naphthalate)],polypropylene, or polyethylene such as HDPE. The middle layers, oftencalled ‘barrier’ or ‘adhesive’ or ‘tie’ layers, are composed of one ormore combinations of either PET, PEN, carboxylated polyethylene ionomersuch as Surlyn®, vinyl alcohol homopolymers or copolymers such aspoly(vinyl alcohol), partially hydrolyzed poly(vinyl acetate),poly(ethylene-co-vinyl alcohol) such as EVOH or EVAL, nylons orpolyamides such as Selar® (DuPont) or polyamides based onmetaxylenediamine (sometimes called nylon MXD-6), or polyvinylidenechloride (PVDC), or polyurethanes.

[0038] Accordingly, the present invention also pertains to a mono- ormulti-layered plastic container or film, stabilized against theformation of aldehydic contaminants during melt processing of saidcontainer or film, comprising at least one layer which comprises

[0039] (a) a polyester, and

[0040] (b) an effective stabilizing amount of an additive combination,wherein the additives are selected from at least two different groups,wherein the groups are

[0041] (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer,

[0042] (ii.) polyhydric alcohols and

[0043] (iii.) polyacrylamide, polymethacrylamide or an acrylamide ormethacrylamide copolymer with at least one ethylenically unsubstitutedcomonomer.

[0044] Rigid containers may be manufactured by known mechanicalprocesses:

[0045] a) Single-stage blow molding such as performed on Nissei, Aoki,or Uniloy machines,

[0046] b) Two-stage, injection molding of pre-forms such as on Netstalor Husky machines, and pre-forms converted to bottles by blow molding(e.g., on Sidel, Corpoplast and Krones machines),

[0047] c) Integrated blow molding of pre-forms to bottles, such asprocesses conducted on Sipa, Krupp Kautex, or Husky ISB machines, and

[0048] d) Stretch blow molding (SBM) of pre-forms to bottles.

[0049] The pre-forms may be mono-layer or multi-layer in construction.The bottles may optionally be post-treated to alter the inner wallproperties. Bottles may optionally be surface treated on the exteriorsuch as by application of surface coatings. UV absorbers and other knownstabilizers may be present in such added surface coatings.

[0050] By the use of known heat-setting techniques, certain of thepolyesters are, in terms of color, I.V. and heat distortion, stable attemperatures up to about 100° C. Such stability characteristics arereferred to herein as “hot-fill” stability. The linear polyesters mostpreferred for use in articles having “hot-fill” stability comprisepoly(ethylene terephthalate), poly(ethylene terephthalate) wherein up to5 mole percent of the ethylene glycol residues have been replaced withresidues derived from 1,4-cyclohexanedimethanol and poly(ethylene2,6-naphthalenedicarboxylate), wherein the polyesters have beensufficiently heat set and oriented by methods well known in the art togive a desired degree of crystallinity.

[0051] The additives of groups (i.), (ii.) and (iii.) are disclosed incopending application Ser. Nos. 09/603,505, 09/603,506 and 09/666,679,the relevant parts of which are each hereby incorporated by reference.

[0052] The additive of group (i.) is poly(vinyl alcohol) or anethylene/vinyl alcohol copolymer.

[0053] Preferably, the additive of group (i.) is an ethylene/vinylalcohol copolymer where the mole ratio of ethylene to vinyl alcohol is99:1 to 1:99. Especially preferred, is the ethylene/vinyl alcoholcopolymer where the mole ratio of ethylene to vinyl alcohol is 50:50 to20:80.

[0054] The ethylene/vinyl alcohol copolymers of group (i.) can be randomor block copolymers.

[0055] The compounds of group (ii.) are polyhydric alcohols of theformula

E—(OH)_(n)

[0056] where

[0057] n is 2 to 4000, and

[0058] E is a hydrocarbyl moiety.

[0059] A hydrocarbyl moiety according to this invention is for examplean aliphatic, cycloaliphatic, aromatic or a mono-, di- orpoly-saccharride moiety.

[0060] The hydrocarbyl moieties for the definition of E may beinterrupted by heteroatoms, for example by —O—.

[0061] Polyhydric alcohols of group (ii.) may be for example glycerin,1,2,3-butanetriol, 1,2,4-butanetriol, erythritol, ribitol, xylitol,dulcitol, sorbitol, 1,2,3-cyclohexatriol, inositol, glucose, galactose,mannose, galacturonic acid, xylose, glucosamine, galactosamine,1,1,2,2-tetramethyloylcyclohexane, 1,1,1-trimethylolpropane,1,1,2-trimethyloylpropane, 1,1,1-trimethylolbutane,1,1,2-trimethylolbutane, 1,1,1-trimethylolpentane,1,1,2-trimethylolpentane, 1,2,2-trimethylolpentane, trimethylolpentane,pentaerythritol, dipentaerythritol, 1,1,3,3-tetrahydroxypropane,1,1,5,5-tetrahydroxypentane, 2,2,6,6-tetrakis(hydroxymethyl)cyclohexaneand 2,2,6,6-tetrakis(hydroxymethyl)cyclohexanol.

[0062] The polyhydric alcohol is for instance starch, cellulose or asugar or a sugar alcohol.

[0063] The polyhydric alcohols include degraded starch (dextrins andcyclodextrins), maltose and its derivatives, maltitol, maltopentaosehydrate, maltoheptaose, maltotetraose, maltulose monohydrate,D,L-glucose, dextrose, sucrose and D-mannitol.

[0064] Commercial polyhydric alcohols include trimethylol propane,triethylol propane, glycerol, sorbitol and pentaerythritol.

[0065] The polymer of group (iii.) is any polymer which contains apolymerized acrylamide or methacrylamide repeating unit. The preparationof acrylamide or methacrylamide polymers is generally known.

[0066] Preferably, the polymer of group (iii.) is polyacrylamide, or acopolymer of acrylamide with another ethylenically unsaturated monomersuch as methacrylamide, styrene, ethylene, an alkyl acrylate, an alkylmethacrylate, N-vinyl-2-pyrrolidinone or acrylonitrile.

[0067] Other preferred comonomers for group (iii.) are the hydroxyalkylmethacrylates, the hydroxyalkyl acrylates or dimethylaminoethylmethacrylate. In these cases, the resulting copolymers contain bothaldehyde reactive amine groups as aldehyde reactive hydroxyl moieties.

[0068] Most preferably, the polymer of group (iii.) is polyacrylamide(PERCOL® 333, Ciba) or polyacrylamide (PERCOL® 351, Ciba).

[0069] The copolymers of group (iii.) can be random or block copolymers.

[0070] It is also contemplated that the compositions may contain othercomponents or modifiers such as stabilizers, dispersants, pigments,colorants, UV absorbers, antioxidants, toughening agents, nucleatingagents and fillers as described in U.S. Pat. No. 5,011,890, thepertinent parts of which are incorporated herein by reference.

[0071] The instant invention also pertains to a process for preventingthe formation of aldehydic contaminants during melt processing of apolyester which comprises

[0072] incorporating into said polyester an effective stabilizing amountof an additive combination, wherein the additives are selected from atleast two different groups, wherein the groups are

[0073] (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer,

[0074] (ii.) polyhydric alcohols and

[0075] (iii.) polyacrylamide, polymethacrylamide or an acrylamide ormethacrylamide copolymer with at least one ethylenically unsubstitutedcomonomer.

[0076] The instant invention also pertains to a process for forming abottle preform or a PET bottle or container suitable for storing water(mineral, natural, ozonated) or other foodstuffs, which allows thedesirable taste of the water or foodstuff after packaging to remainunaltered after being placed in said bottle or container prepared fromthe polyester composition of the instant invention.

[0077] The instant plastic container or film stabilized by a compound orcompounds of component (b) may also optionally have incorporated thereinor applied thereto from about 0.01 to about 10% by weight; preferablyfrom about 0.025 to about 5% by weight, and most preferably from about0.1 to about 3% by weight, based on the total weight of the composition,of additional coadditives such as antioxidants, other UV absorbers,hindered amines, phosphites or phosphonites, benzofuran-2-ones,thiosynergists, polyamide stabilizers, metal stearates, nucleatingagents, fillers, reinforcing agents, lubricants, emulsifiers, dyes,pigments, optical brighteners, flame retardants, antistatic agents,blowing agents and the like, such as the materials listed below, ormixtures thereof.

[0078] 1. Antioxidants

[0079] 1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linearor branched in the side chains, for example,2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1-methylundec-1-yl)phenol,2,4-dimethyl-6-(1-methylheptadec-1-yl)phenol,2,4-dimethyl-6-(1-methyltridec-1-yl)phenol and mixtures thereof.

[0080] 1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

[0081] 1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

[0082] 1.4. Tocopherols, for example α-tocopherol, β-tocopherol,γ-tocopherol, δ-tocopherol and mixtures thereof (Vitamin E).

[0083] 1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis-(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.

[0084] 1.6. Alkylidenebisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3-tert-butyl-4-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′tert-butyl-2-hydroxy-5-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

[0085] 1.7. Benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl4-hydroxybenzyl)amine,1,3,5-tri-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,di-(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide,3,5-di-tert-butyl-4-hydroxybenzyl-mercapto-acetic acid isooctyl ester,bis-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol terephthalate,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate,1,3,5-tris-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid dioctadecyl ester and3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid monoethyl ester,calcium-salt.

[0086] 1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate,di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

[0087] 1.9. Aromatic hydroxybenzyl compounds, for example1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

[0088] 1.10. Triazine compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxy-benzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

[0089] 1.11. Benzylphosphonates, for exampledimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate,diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, thecalcium salt of the monoethyl ester of3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

[0090] 1.12. Acylaminophenols, for example 4-hydroxy-lauric acidanilide, 4-hydroxy-stearic acid anilide,2,4-bis-octylmercapto-6-(3,5-tert-butyl-4-hydroxyanilino)-s-triazine andoctyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)-carbamate.

[0091] 1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionicacid with mono- or polyhydric alcohols, e.g. with methanol, ethanol,n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

[0092] 1.14. Esters ofβ-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- orpolyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis-(hydroxyethyl)oxamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

[0093] 1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionicacid with mono- or polyhydric alcohols, e.g. with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

[0094] 1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

[0095] 1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionicacid e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide,N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide(Naugard®XL-1 supplied by Uniroyal).

[0096] 1.18. Ascorbic acid (vitamin C)

[0097] 1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenlenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyl-diphenylamines, a mixture of mono- anddialkylated nonyldiphenylamines, a mixture of mono- and dialkylateddodecyidiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyidiphenylamines, a mixture of mono- and dialkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylatedtert-octyl-phenothiazines, N-allylphenothiazin,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis-(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl)-sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

[0098] 2. UV absorbers and light stabilizers

[0099] 2.1. 2-(2-Hydroxyphenyl)-2H-benzotriazoles, for example knowncommercial hydroxyphenyl-2H-benzotriazoles and benzotriazoles asdisclosed in, U.S. Pat. Nos. 3,004,896; 3,055,896; 3,072,585; 3,074,910;3,189,615; 3,218,332; 3,230,194; 4,127,586; 4,226,763; 4,275,004;4,278,589; 4,315,848; 4,347,180; 4,383,863; 4,675,352; 4,681,905,4,853,471; 5,268,450; 5,278,314; 5,280,124; 5,319,091; 5,410,071;5,436,349; 5,516,914; 5,554,760; 5,563,242; 5,574,166; 5,607,987 and5,977,219, such as 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3,5-di-t-butyl-2-hydroxyphenyl)-2H-benzotriazole,2-(2-hydroxy-5-t-butylphenyl)-2H-benzotriazole,2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole,5-chloro-2-(3,5-di-t-butyl-2-hydroxyphenyl)-2H-benzotriazole,5-chloro-2-(3-t-butyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3-sec-butyl-5-t-butyl-2-hydroxyphenyl)-2H-benzotriazole,2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole,2-(3,5-di-t-amyl-2-hydroxyphenyl)-2H-benzotriazole,2-(3,5-bis-α-cumyl-2-hydroxyphenyl)-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-(ω-hydroxy-octa-(ethyleneoxy)carbonyl-ethyl)-,phenyl)-2H-benzotriazole,2-(3-dodecyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-octyloxycarbonyl)ethylphenyl)-2H-benzotriazole,dodecylated 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-octyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,2-(3-tert-butyl-5-(2-(2-ethylhexyloxy)-carbonylethyl)-2-hydroxyphenyl)-5-chloro-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-2H-benzotriazole,2-(3-t-butyl-5-(2-(2-ethylhexyloxy)carbonylethyl)-2-hydroxyphenyl)-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl-2H-benzotriazole,2,2′-methylene-bis(4-t-octyl-(6-2H-benzotriazol-2-yl)phenol),2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole,2-(2-hydroxy-3-t-octyl-5-α-cumylphenyl)-2H-benzotriazole,5-fluoro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-chloro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-chloro-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole,2-(3-t-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-t-octylphenyl)-2H-benzotriazole,methyl3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyhydrocinnamate,5-butylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-t-butylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole,5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole,5-butylsulfonyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole and5-phenylsulfonyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole.

[0100] 2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy,4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy,4,2′,4′-trihydroxy and 2′-hydroxy-4,4′-dimethoxy derivatives.

[0101] 2.3. Esters of substituted and unsubstituted benzoic acids, asfor example 4-tertbutyl-phenyl salicylate, phenyl salicylate,octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

[0102] 2.4. Acrylates and malonates, for example,α-cyano-β,β-diphenylacrylic acid ethyl ester or isooctyl ester,α-carbomethoxy-cinnamic acid methyl ester,α-cyano-β-methyl-p-methoxy-cinnamic acid methyl ester or butyl ester,α-carbomethoxy-p-methoxy-cinnamic acid methyl ester,N-(β-carbomethoxy-β-cyanovinyl)-2-methyl-indoline, Sanduvor® PR25,dimethyl p-methoxybenzylidenemalonate (CAS# 7443-25-6), and Sanduvor®PR31, di-(1,2,2,6,6-pentamethylpiperidin-4-yl)p-methoxybenzylidenemalonate (CAS #147783-69-5).

[0103] 2.5. Nickel compounds, for example nickel complexes of2,2′-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. themethyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenylundecylketoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additionalligands.

[0104] 2.6. Sterically hindered amine stabilizers, for example4-hydroxy-2,2,6,6-tetramethylpiperidine,1-allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine,1-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine,bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl) succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decan-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, linear or cycliccondensates ofN,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decane and epichlorohydrin,1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,diester of 4-methoxy-methylene-malonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane,reaction product of maleic acid anhydride-α-olefin-copolymer with2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

[0105] The sterically hindered amine may also be one of the compoundsdescribed in GB-A-2301106 as component I-a), I-b), I-c), I-d), I-e),I-f), I-g), I-h), I-i), I-j), I-k) or I-l), in particular the lightstabilizer 1-a-1, 1-a-2, 1-b-1, 1-c-1, 1-c-2, 1-d-1, 1-d-2, 1-d-3,1-e-1, 1-f-1, 1-g-1, 1-g-2 or 1-k-1 listed on pages 68 to 73 of saidGB-A-2301106.

[0106] The sterically hindered amine may also be one of the compoundsdescribed in EP 782994, for example compounds as described in claims 10or 38 or in Examples 1-12 or D-1 to D-5 therein.

[0107] 2.7. Sterically hindered amines substituted on the N-atom by ahydroxy-substituted alkoxy group, for example compounds such as1-(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine,1-(2-hydroxy-2-methylpropoxy)-4-hexadecanoyloxy-2,2,6,6-tetramethylpiperidine,the reaction product of 1-oxyl-4-hydroxy-2,2,6,6-tetramethylpiperidinewith a carbon radical from t-amylalcohol,1-(2-hydroxy-2-methylpropoxy)-4-hydroxy-2,2,6,6-tetramethylpiperidine,1-(2-hydroxy-2-methylpropoxy)-4-oxo-2,2,6,6-tetramethylpiperidine,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)adipate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)succinate,bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)glutarate and2,4-bis{N-[1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl]-N-butylamino}-6-(2-hydroxyethylamino)-s-triazine.

[0108] 2.8. Oxamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, mixtures of o- andp-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

[0109] 2.9. Tris-aryl-o-hydroxyphenyl-s-triazines, for example knowncommercial tris-aryl-o-hydroxyphenyl-s-triazines and triazines asdisclosed in, WO 96/28431, EP 434608, EP 941989, GB 2,317,893, U.S. Pat.Nos. 3,843,371; 4,619,956; 4,740,542; 5,096,489; 5,106,891; 5,298,067;5,300,414; 5,354,794; 5,461,151; 5,476,937; 5,489,503; 5,543,518;5,556,973; 5,597,854; 5,681,955; 5,726,309; 5,942,626; 5,959,008;5,998,116 and 6,013,704, for example4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-octyloxyphenyl)-s-triazine,Cyasorb® 1164, Cytec Corp,4,6-bis-(2,4-dimethylphenyl)-2-(2,4-dihydroxyphenyl)-s-triazine,2,4-bis(2,4-dihydroxyphenyl)-6-(4-chlorophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(2,4-dimethylphenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(4-bromophenyl)-s-triazine,2,4-bis[2-hydroxy-4-(2-acetoxyethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine,2,4-bis(2,4-dihydroxyphenyl)-6-(2,4-dimethylphenyl)-s-triazine,2,4-bis(4-biphenylyl)-6-(2-hydroxy-4-octyloxycarbonylethylideneoxyphenyl)-s-triazine,2-phenyl-4-[2-hydroxy-4-(3-sec-butyloxy-2-hydroxypropyloxy)phenyl]-6-[2-hydroxy-4-(3-sec-amyloxy-2-hydroxypropyloxy)-phenyl]-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-benzyloxy-2-hydroxypropyloxy)phenyl]-s-triazine,2,4-bis(2-hydroxy-4-n-butyloxyphenyl)-6-(2,4-di-n-butyloxyphenyl)-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-nonyloxy*-2-hydroxypropyloxy)-5-α-cumylphenyl]-s-triazine(* denotes a mixture of octyloxy, nonyloxy and decyloxy groups),methylenebis-{2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-butyloxy-2-hydroxypropoxy)-phenyl]-s-triazine},methylene bridged dimer mixture bridged in the 3:5′, 5:5′ and 3:3′positions in a 5:4:1 ratio,2,4,6-tris(2-hydroxy-4-isooctyloxycarbonylisopropylideneoxyphenyl)-s-triazine,2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy4-hexyloxy-5-α-cumylphenyl)-s-triazine,2-(2,4,6-trimethylphenyl)-4,6-bis[2-hydroxy-4-(3-butyloxy-2-hydroxypropyloxy)phenyl]-s-triazine,2,4,6-tris[2-hydroxy-4-(3-sec-butyloxy-2-hydroxypropyloxy)phenyl]-s-triazine,mixture of4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-dodecyloxy-2-hydroxypropoxy)-phenyl)-s-triazineand4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-tridecyloxy-2-hydroxypropoxy)-phenyl)-s-triazine,Tinuvin® 400, Ciba Specialty Chemicals Corp.,4,6-bis-(2,4-dimethylphenyl)-2-(2-hydroxy-4-(3-(2-ethylhexyloxy)-2-hydroxypropoxy)-phenyl)-s-triazineand 4,6-diphenyl-2-(4-hexyloxy-2-hydroxyphenyl)-s-triazine.

[0110] 3. Metal deactivators, for example N,N′-diphenyloxamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl) hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

[0111] 4. Phosphites and phosphonites, for example triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite,diisodecyloxypentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-dibenzo[d,f][1,3,2]dioxaphosphepin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenzo[d,g][1,3,2]dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite,2,2′,2″-nitrilo[triethyltris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite.

[0112] Especially preferred are the following phosphites:

[0113] Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168, CibaSpecialty Chemicals Corp.), tris(nonylphenyl) phosphite,

[0114] 5. Benzofuranones and indolinones, for example those disclosed inU.S. Pat. Nos. 4,325,863, 4,338,244, 5,175,312, 5,216,052, 5,252,643;DE-A-4316611; DE-A-4316622; DE-A4316876; EP-A-0589839 or EP-A-0591102 or3-[4-(2-acetoxyethoxy)-phenyl]-5,7-di-tert-butyl-benzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]-benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, Irganox®HP-136, Ciba Specialty Chemicals Corp., and3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

[0115] 6. Thiosynergists, for example dilauryl thiodipropionate ordistearyl thiodipropionate.

[0116] 7. Peroxide scavengers, for example esters of β-thiodipropionicacid, for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

[0117] 8. Polyamide stabilizers, for example copper salts in combinationwith iodides and/or phosphorus compounds and salts of divalentmanganese.

[0118] 9. Basic co-stabilizers, for example melamine,polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, ureaderivatives, hydrazine derivatives, amines, polyamides, polyurethanes,alkali metal salts and alkaline earth metal salts of higher fatty acids,for example, calcium stearate, zinc stearate, magnesium behenate,magnesium stearate, sodium ricinoleate and potassium palmitate, antimonypyrocatecholate or zinc pyrocatecholate.

[0119] 10. Nucleating agents, for example inorganic substances such astalcum, metal oxides such as titanium dioxide or magnesium oxide,phosphates, carbonates or sulfates of, preferably, alkaline earthmetals; organic compounds such as mono- or polycarboxylic acids and thesalts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid,diphenylacetic acid, sodium succinate or sodium benzoate; polymericcompounds such as ionic copolymers (ionomers).

[0120] 11. Fillers and reinforcing agents, for example calciumcarbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin,mica, barium sulfate, metal oxides and hydroxides, carbon black,graphite, wood flour and flours or fibers of other natural products,synthetic fibers.

[0121] 12. Dispersing Agents, such as polyethylene oxide waxes ormineral oil.

[0122] 13. Other additives, for example plasticizers, lubricants,emulsifiers, pigments, dyes, optical brighteners, rheology additives,catalysts, flow-control agents, slip agents, crosslinking agents,crosslinking boosters, halogen scavengers, smoke inhibitors,flameproofing agents, antistatic agents, clarifiers such as substitutedand unsubstituted bisbenzylidene sorbitols, benzoxazinone UV absorberssuch as 2,2′-p-phenylene-bis(3,1-benzoxazin-4-one), Cyasorb® 3638 (CAS#18600-59-4), and blowing agents.

[0123] The following examples are for illustrative purposes only and arenot to be construed to limit the scope of the instant invention in anymanner whatsoever.

[0124] General—PET bottle grade pellets are subjected to extrusioncompounding to simulate the heat history which PET experiences whenthermally injection molded into bottle preforms and subsequentlystretch-blow molded into bottles. The efficacy of an additive added toreduce the formation of acetaldehyde is determined by quantitativeanalysis using thermal desorption GC-MS after adoption of publishedmethods. An unstabilized PET is extruded each day to provide a controlpolymer for measuring acetaldehyde formation.

[0125] Extrusion—PET is pre-dried in vacuo under nitrogen at an oventemperature of about 70° C. to a moisture level of about 30 ppm which isverified on a Mitsubishi VA-O6 moisturemeter. A Leistritz 18 mm or 27 mmcorotating, non-intermeshing twin screw extruder is configured asfollows: set temps=throat (220-230° C.), zones and die (270° C.), actualextrudate melt temperature is 275-280° C., screw at 100-110 rpm, hopperfeeder=10-15 ppm.

[0126] PET Pellet Color—Yellowness Index (YI), and L*, a*, b* by ASTMD1925, D65 10 degm specular included, measured on PET pellets using aDCI spectrophotometer.

[0127] Acetaldehyde Analysis—The concentration of acetaldehyde in PET isquantitatively determined using a thermal desorption GC-MS methodadapted from B. Nijassen et al., Packaging Technology and Science, 9,175 (1996); S. Yong Lee, SPE ANTEC 1997, pp 857-861; and M. Dong et al.,J. Chromatographic Science, 18, 242 (1980). A general example followsbelow:

[0128] The PET samples are analyzed, in duplicate, by weighing 250 mg ofpowdered PET pellets (cryogenically pulverized) in a 5 mL crimp sealedheadspace vial. The sample vial is heated at 120° C. for one hour in aTekmar model 5000 static headspace analyzer. The headspace gas (5 cc) isthen transferred via a heated transfer line to a Fisons MD-800 GC-MSsystem for SIR detection of the acetaldehyde. The acetaldehyde isdetected by monitoring its fragment ions of 29 and 44 m/e. The Total IonCurrent (TIC) of the GC-MS is also monitored in the retention timeregion of 4-8 minutes. By doing this the presence of acetaldehyde in thesamples is confirmed by three different detectors. By using a knownacetaldehyde value for PET, the ratio of peak areas for the known PETresin and for the experimental PET resin blends are compared and theamount of acetaldehyde in the experimental blend can be obtained.

[0129] Haze—PET blends are injection molded into 2″×2″×60 mil plaquesusing a BOY 50M Injection Molder at a die temperature of 550° F. (288°C.). A BYK-Gardner Haze meter is used to measure haze. “Haze” is anundesirable, perceptible graying effect.

EXAMPLE 1

[0130] Unstabilized commercial PET (CLEARTUF® 7207, Shell) is used as acontrol PET. Several additive combinations listed below demonstrate asignificant reduction in the amount of acetaldehyde (AA) versus theamount seen when unstabilized PET is extrusion compounded. The % AAreduction is the amount less compared to the amount of AA in thecontrol. The total ion current (TIC) data run in triplicate for thecontrol PET has a standard deviation of s=0.35. Parts per million (ppm)additive is based on resin. Formulation Additives A (control) none B2500 ppm polyacrylamide, Percol ® 333 (Ciba)  400 ppm poly(vinylalcohol), PVA C 2500 ppm polyacrylamide, Percol ® 333 (Ciba) 1600 ppmcellulose D  400 ppm poly(vinyl alcohol), PVA 1600 ppm cellulose E 2500ppm polyacrylamide, Percol ® 351 (Ciba)  400 ppm poly(vinyl alcohol),PVA F 2500 ppm polyacrylamide, Percol ® 333 (Ciba)  400 ppm poly(vinylalcohol), PVA 1600 ppm cellulose G  750 ppm ethylene/vinyl alcoholcopolymer, 40% ethylene 2000 ppm starch H  750 ppm ethylene/vinylalcohol copolymer, 40% ethylene 1000 ppm starch 1000 ppm cellulose

[0131] The use of the present additive combinations results in thereduction of acetaldehyde versus the control and provides for excellentcolor control and low haze formation.

[0132] When polyacrylamide, Percol® 333 or Percol® 351 are interchangedin the above formulations, excellent results for aldehyde inhibition,low color and low haze are seen. When starch and cellulose areinterchanged in the above formulations, excellent results for aldehydeinhibition, low color and low haze are seen. When poly(vinyl alcohol),PVA, ethylene/vinyl alcohol copolymer, 40%, 38%, 32% or 27% ethylene,are interchanged in the above formulations, excellent results foraldehyde inhibition, low color and low haze are seen.

What is claimed is:
 1. A polyester composition, stabilized against the formation of aldehydic contaminants during melt processing of said polyester, which comprises (a) a polyester, and (b) an effective stabilizing amount of an additive combination, wherein the additives are selected from at least two different groups, wherein the groups are (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer, (ii.) polyhydric alcohols and (iii.) polyacrylamide, polymethacrylamide or an acrylamide or methacrylamide copolymer with at least one ethylenically unsubstituted comonomer.
 2. A composition according to claim 1 wherein the polyester of component (a) is 95-99.9% by weight of the stabilized composition; and the additive combination of component (b) is 5 to 0.1% by weight of the stabilized composition.
 3. A composition according to claim 1 wherein the polyester of component (a) has dicarboxylic acid repeat units selected from the group consisting of aromatic dicarboxylic acids having 8 to 14 carbon atoms, aliphatic dicarboxylic acids having 4 to 12 carbon atoms, cycloaliphatic dicarboxylic acids having 8 to 12 carbon atoms, and mixtures thereof.
 4. A composition according to claim 3 wherein the dicarboxylic acid is terephthalic acid, isophthalic acid, o-phthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4′-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and mixtures thereof.
 5. A composition according to claim 4 wherein the dicarboxylic acid is terephthalic acid or 2,6-naphthalene dicarboxylic acid.
 6. A composition according to claim 1 wherein the diol portion of the polyester of component (a) is derived from the generic formula HO—R—OH where R is an aliphatic, cycloaliphatic or aromatic moiety of 2 to 18 carbon atoms.
 7. A composition according to claim 6 wherein the diol is ethylene glycol, diethylene glycol, triethylene glycol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 1,4-cyclohexanedimethanol, 3-methylpentane-2,4-diol, 2-methylpentane, 1,4-diol, 2,2-diethylpropane-1,3-diol, 1,4-di-(hydroxyethoxy)benzene, 2,2-bis(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis-(3-hydroxyethoxyphenyl)propane, 2,2-bis-(4-hydroxypropoxyphenyl)ethane and mixtures thereof.
 8. A composition according to claim 7 wherein the diol is ethylene glycol.
 9. A composition according to claim 1 wherein the polyester of component (a) is poly(ethylene terephthalate) PET or poly(ethylene 2,6-naphthalene-2,6-dicarboxylate).
 10. A composition according to claim 9 wherein the polyester is poly(ethylene terephthalate).
 11. A composition according to claim 1 wherein the additive of group (i.) is an ethylene/vinyl alcohol copolymer.
 12. A composition according to claim 11 wherein the additive of group (i.) is an ethylene/vinyl alcohol copolymer where the mole ratio of ethylene to vinyl alcohol is 99:1 to 1:99.
 13. A composition according to claim 12 where in the ethylene/vinyl alcohol copolymer the mole ratio of ethylene to vinyl alcohol is 50:50 to 20:80.
 14. A composition according to claim 1 wherein the polyhydric alcohol of group (ii.) is starch, cellulose or a sugar or a sugar alcohol.
 15. A composition according to claim 14 wherein the polyhydric alcohol is cellulose or starch.
 16. A composition according to claim 1 wherein the polyhydric alcohol is selected from the group consisting of degraded starch (dextrins and cyclodextrins), maltose and its derivatives, maltitol, maltopentaose hydrate, maltoheptaose, maltotetraose, maltulose monohydrate, D,L-glucose, dextrose, sucrose and D-mannitol.
 17. A composition according to claim 1 wherein the polyhydric alcohol is selected from the group consisting of trimethylol propane, triethylol propane, glycerol, sorbitol, pentaerythritol and dipentaerythritol.
 18. A composition according to claim 1 wherein the additive of group (iii.) is any polymer which contains a polymerized acrylamide or methacrylamide repeating unit.
 19. A composition according to claim 18 wherein the additive of group (iii.) is polyacrylamide, polymethacrylamide or a copolymer of acrylamide or methacrylamide with another ethylenically unsaturated monomer which is acrylamide, methacrylamide, styrene, ethylene, an alkyl acrylate, an alkyl methacrylate, N-vinyl-2-pyrrolidinone or acrylonitrile.
 20. A composition according to claim 18 wherein the additive of group (iii.) is a copolymer of acrylamide or methacrylamide with another ethylenically unsaturated monomer which is a hydroxyalkyl methacrylate, a hydroxyalkyl acrylate or dimethylaminoethyl methacrylate.
 21. A composition according to claim 18 wherein the additive of group (iii.) is polyacrylamide.
 22. A process for preventing the formation of aldehydic contaminants during melt processing of a polyester which comprises incorporating into said polyester an effective stabilizing amount of an additive combination, wherein the additives are selected from at least two different groups, wherein the groups are (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer, (ii.) polyhydric alcohols and (iii.) polyacrylamide, polymethacrylamide or an acrylamide or methacrylamide copolymer with at least one ethylenically unsubstituted comonomer.
 23. A mono- or multi-layered plastic container or film, stabilized against the formation of aldehydic contaminants during melt processing of said container or film, comprising at least one layer which comprises (a) a polyester, and (b) an effective stabilizing amount of an additive combination, wherein the additives are selected from at least two different groups, wherein the groups are (i.) poly(vinyl alcohol) or ethylene/vinyl alcohol copolymer, (ii.) polyhydric alcohols and (iii.) polyacrylamide, polymethacrylamide or an acrylamide or methacrylamide copolymer with at least one ethylenically unsubstituted comonomer.
 24. A plastic container according to claim 19 which is a rigid bottle. 